WOODSTOWN, N.J. - It's a big message from a small town: The government is spraying the skies with chemicals to control our lives - and maybe kill us.

A billboard in this picturesque Salem County community has been delivering the jolting news, listing a website of a large and vocal environmental group known as Bye Bye Blue Sky that alleges a global conspiracy.

Its proof: Just look up and see all those white contrails spewing from jets, obscuring the blue sky. The streams - called "chem-trails" - are said to contain noxious chemicals or biological agents meant to manipulate our minds, control the population, and/or wage planetwide warfare.

"This is extremely dangerous," said Suzanne Maher, an activist from outside Toronto who started Bye Bye Blue Sky. "This is genocide."

Chem-trails have gotten so much attention lately that the National Academy of Sciences saw the need to address them in recent meetings. A spokesman for the academy, a private, nonprofit organization of the country's leading researchers, said people across America are deluging federal agencies with thousands of complaint letters. Last month, a group of two dozen activists held a rally in Center City to protest chem-trails.

Some people have informed the internet that Prince, who warned of chem-trails, died of "chem-trail flu," while Kylie Jenner has tweeted in alarm about them.

While the science establishment debunks chem-trails, Bye Bye is spreading the word via the internet as well as by billboards throughout North America. A friend of Maher's, Sharon LePere, a 64-year-old retired health-care worker, organized a $1,485 GoFundMe campaign to help pay for the Woodstown billboard, the first in the United States.

No longer up, the billboard is expected to be back in June so Shore-bound motorists can see it, LePere said. It's a vital issue, she added.

"The people in charge of this technology control our weather and our food," LePere said. "I know the whole thing sounds crazy, but we're being poisoned by nanoparticles that are killing our trees and increasing cloud cover."

That a cabal of government, military, and industry miscreants is secretly playing God and sowing terror from the skies is deemed highly unlikely by researchers.

"It is not happening," agreed David Titley, director of the Pennsylvania State University Center for Solutions to Weather and Climate Risk, and a retired Navy rear admiral.

As Joyce Penner, professor of atmospheric science and cloud expert at the University of Michigan, put it: "What they talk about is a bit crazy."

Scientists describe jet contrails as water vapor - nothing sinister. And while Blue Sky people are correct in saying a sky crosshatched by white streams is less blue than it was in Lincoln's day, scientists explain that it's an unavoidable by-product of the modern age of aviation.

As outlandish as researchers find the Bye Bye theories, however, real science lies behind some fears that the organization professes.

Specifically, scientists believe the climate can be engineered, or geo-engineered, as they call it.

It works like this: Climate science tells us the Earth is warming from an abundance of carbon dioxide, also called greenhouse gas because it makes the atmosphere absorb heat.

If we were to adequately lower the amount of carbon dioxide in the atmosphere, global warming would be diminished.

But that could take years - decades, possibly. So, as electrical and computer engineering professor Granger Morgan of Carnegie Mellon University in Pittsburgh wrote, "It is imperative for the survival of the planet ... that there be a Plan B."

What science has come up with is a climate intervention called solar radiation management. The idea is to pump large amounts of particles into the stratosphere to reflect sunlight.

While this is primarily a theory, such effects have been demonstrated in real life. When giant volcanoes have erupted in the past, they spewed gases that converted into sulfate particles, which reflected sunlight and cooled the Earth, at least temporarily.

So, scientists argue, if global warming got to a crisis point, we could theoretically pump reflective particles skyward, cooling the planet quickly, maybe even in a matter of days.

The downside is, however, that it would do nothing to reduce greenhouse gas. And no one knows the long-term effects. Would rainfall be adversely affected? Or agriculture?

The whole idea is "barking mad," writes Raymond Pierrehumbert, a University of Oxford physicist who wants us to steer clear of climate tinkering, saying, "We have only one planet to live on, and can't afford any bad mistakes."

Although such "riskier ideas" like solar radiation management shouldn't be deployed now, "they should be studied so that we can provide answers if someday these ideas begin to be considered in attempts to avert catastrophe," wrote Ralph Cicerone, president of the National Academy of Sciences.

Not buying the notion that all of this is only in the drawing board stage, the Bye Bye Blue Sky folks say climate intervention is going on now, but with twisted purpose.

"The government wants a complacent, docile society to do its bidding" by dropping various chemicals and elements on people from the sky, said Maher. The United Nations is in on it, too, she added: "They want to kill and control people."

Penn State's Titley said a Bye Bye-size conspiracy would be too big to conceal.

"Imagine if nobody knew of Federal Express, but they saw packages magically showing up everywhere," he said. "This conspiracy would be like hiding something as big as FedEx without anybody knowing it."

As fervent as the Bye Bye people are, their message may not be getting out clearly to the uninitiated.

"I noticed the billboard for weeks," said Laura Chard, 52, owner of Cuckoo's Nest Salon. "I just didn't know what it meant. And people aren't talking about it."